Today I have been mostly laying under the vehicle cursing and bruising my lower arms trying to remove 5 particularly nasty fixings. One of nuts on the turbo exhaust outlet I think must have recut the thread it took so much effort to turn it along the whole length of the stud, (which has a nice shiny (crossed) thread now - it would be the one closest the bulkhead, so you can't use a long lever on it to remove). The turbo is out now though! - next step, clean, replace core, and simply follow the procedure in reverse, not forgetting a drop of oil.
Hands and arms too bruised to do too much more today, but once they recover I'll either re-tap that thread on the stud, or if I feel brave enough, remove the stud and replace it with one of the new ones that will be coming with the turbo fitting kit. Another step closer in getting it back on the road...